The Girls Just Wanna Have Fun hitmaker's mother Catrine divorced her dad Fred when the singer was only five years old, but she later remarried and moved the family in with her new husband.

However, Lauper admits life quickly became unbearable when her stepfather began beating her mum and threatening to rape the Grammy winner and her older sister Elen.

Detailing the horrific experience in upcoming book Cyndi Lauper: A Memoir, she writes, "Unfortunately, she married a paedophile who beat her and bullied her. He'd threaten to beat her parents and rape her daughters while she was at work."

And in another excerpt, obtained by the New York Post, the 59 year old insists she could no longer bear living at home after catching him as he watched her take a bath: "I heard his creepy giggle and saw my stepfather's pear-shaped shadow... It was too much. It was worse than him beating the dog when she cried... It was worse than him touching himself, right outside our bedroom window."